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Nov. 4, 2010 -- Researchers have found that a drug used to treat autoimmune disorders effectively increased growth rates among children with juvenile idiopathic arthritis (JIA), a disease that affects children’s joints and can stymie their growth rates.

Researchers led by Edward H. Giannini, MSc, DrPH, of Cincinnati Children’s Hospital Medical Center, compared three types of treatment among 594 children ages 2 to 18 with JIA. The participants received one of three treatments: etanercept, a drug used to treat autoimmune disorders sold under the brand name Enbrel; methotrexate, a drug used to treat inflammatory arthritis that is sold under the brand names Trexall or Rheumatrex; or etanercept plus methotrexate.

The majority of patients were female, white, and had used nonsteroidal anti-inflammatory drugs to treat their symptoms. The children’s height, weight, and body mass index (BMI) were measured at the start of the study and then again at one, two, and three years afterward and their measurements were compared with CDC standardized growth charts. Overall, the children taking etanercept or etanercept plus methotrexate experienced steadily increasing improvements in height, weight, and BMI compared with those who took methotrexate alone.

Improvement in Growth

During the three-year study period, the researchers found that:

Children taking etanercept alone grew in height by an increase of 4.8 percentile points, gained weight by 13 percentile points, and increased their BMI between 9.8 and 13.8 percentile points three years after the study began.

Children who took the combination treatment of etanercept plus methotrexate also grew in height by 5.6 percentile points, gained weight by 8.4 percentile points, and increased their BMI between 2.1 and 5.2 percentile points three years after the study began.

These improvements in height, weight, and BMI were not observed in those children who only took methotrexate.

About 300,000 children in the U.S. have some form of juvenile arthritis, causing stiffness, joint pain, inflammation, and possibly reduced physical growth and development.

“Studies have shown that growth retardation is associated with systemic inflammation and is a potentially permanent complication of JIA,” Giannini says in a news release. “Restoring normal growth development is a relevant goal of anti-inflammatory treatment in JIA patients and our study showed significant increases in height, weight, and BMI percentiles for those treated with etanercept alone or in combination with methotrexate.”